My baby has a red tip of the penis, it is around his urethra to the end of the skin connected to the prepuce. It does not seem to be painful.

Based on the symptoms described, it is possible that the redness on the tip of the penis is caused by irritation due to moisture and friction from the diaper. The best course of action would be to apply a zinc cream with at least 20% zinc at each diaper change, use disposable diapers while using the cream, and ensure the area is kept clean and dry before applying the cream. Avoid using scented soap, antiseptics, or pulling back the foreskin to reach the skin underneath. If the redness persists after 3-4 days of treatment, spreads to other areas, or if symptoms of infection such as fever or pain develop, it would be advisable to consult a doctor for proper diagnosis and treatment. Additionally, cleaning your cloth diapers properly according to the manufacturer's instructions or a recommended guide can help prevent further irritation. Incorporating products like liniment or a protective balm on the scrotum and penis can also be beneficial in preventing or treating redness.